Silver Dream Machine - aka campervan mk2

[richbee]

Nice, I need to get my van sold!

Good time of year for it, while it's spring & the sun is shining - so basically you've got til about Wednesday

[richbee]

Not carried out much testing but the 390W was generating enough spot power to do an induction hob 1 gallon chilli con cook for about 3 hrs without depleting the battery at all.

I now appreciate the value of the extra capacity so we can go onto the evening with a fully charged battery regardless of what we are likely to get up to through the day

That sounds exactly what I'm after
It's a shame that they are much more expensive than a single 400/500W house panel, but not that much in the grand scheme

[richbee]

There are very likely 4x LF280k cells in there. Feels like madness to pay £400 for that when these are under £50: https://www.fogstar.co.uk/collections/l ... ll-grade-b

But you need 4 of them, plus case & BMS etc? Is there a readily available BMS for 12v systems?

There are plenty of 4s BMSs available, typically between £50-100 depending on how much power you want it to handle (100-400A).

Edited to add that you don't necessarily need a BMS that can handle all the current you want. You can have the BMS control a relay. Eg : https://www.ebay.co.uk/itm/226477740044

Thanks - I'll have a look.
I'm doing as much as I can myself to save costs, as I've got time on my hands, so it might be worth it, and it's all good skills and very satisfying to have things diy

[Joeboy]

Not carried out much testing but the 390W was generating enough spot power to do an induction hob 1 gallon chilli con cook for about 3 hrs without depleting the battery at all.

I now appreciate the value of the extra capacity so we can go onto the evening with a fully charged battery regardless of what we are likely to get up to through the day

That sounds exactly what I'm after
It's a shame that they are much more expensive than a single 400/500W house panel, but not that much in the grand scheme

Yes but as you say, with the smaller units you can generally keep the existing skylights. We've kept all three. Me n swmbo are off to France for a bit late June so will report back on how well the solar rig & LA hold up to daily use.

Coming from a 100W panel to the 390W and knowing there would be a leap, I'm still quite surprised at how much we can get done and still go into the dark with a fully charged battery. Horses for courses of course but mind and look into paring back actual drain. You might get further than you'd think.

If on the other hand you plunge headlong into 4S fanciness I'll be eager to read the results.

[richbee]

Not carried out much testing but the 390W was generating enough spot power to do an induction hob 1 gallon chilli con cook for about 3 hrs without depleting the battery at all.

I now appreciate the value of the extra capacity so we can go onto the evening with a fully charged battery regardless of what we are likely to get up to through the day

That sounds exactly what I'm after
It's a shame that they are much more expensive than a single 400/500W house panel, but not that much in the grand scheme

Yes but as you say, with the smaller units you can generally keep the existing skylights. We've kept all three. Me n swmbo are off to France for a bit late June so will report back on how well the solar rig & LA hold up to daily use.

Coming from a 100W panel to the 390W and knowing there would be a leap, I'm still quite surprised at how much we can get done and still go into the dark with a fully charged battery. Horses for courses of course but mind and look into paring back actual drain. You might get further than you'd think.

If on the other hand you plunge headlong into 4S fanciness I'll be eager to read the results.

The previous van only had an 80w panel, plus 130Ah lead acid battery, but it was only running a 12v fridge plus lights & usb charging - it always managed without problems. It will depend greatly on the amount of sun and how long we're away for, now that we're wanting it to do a lot more.

[richbee]

There are very likely 4x LF280k cells in there. Feels like madness to pay £400 for that when these are under £50: https://www.fogstar.co.uk/collections/l ... ll-grade-b

But you need 4 of them, plus case & BMS etc? Is there a readily available BMS for 12v systems?

There are plenty of 4s BMSs available, typically between £50-100 depending on how much power you want it to handle (100-400A).

Edited to add that you don't necessarily need a BMS that can handle all the current you want. You can have the BMS control a relay. Eg : https://www.ebay.co.uk/itm/226477740044

So fogstar sell a complete kit - 310Ah with cells, case & bms for £350.
But - it says, the cells need to be top balanced by charging to 3.65 volts. What do I need to do that?
Fogstar sell a balancer, but it is only suitable for their drift pro batteries

[Stinsy]

But you need 4 of them, plus case & BMS etc? Is there a readily available BMS for 12v systems?

There are plenty of 4s BMSs available, typically between £50-100 depending on how much power you want it to handle (100-400A).

Edited to add that you don't necessarily need a BMS that can handle all the current you want. You can have the BMS control a relay. Eg : https://www.ebay.co.uk/itm/226477740044

So fogstar sell a complete kit - 310Ah with cells, case & bms for £350.
But - it says, the cells need to be top balanced by charging to 3.65 volts. What do I need to do that?
Fogstar sell a balancer, but it is only suitable for their drift pro batteries

1) People who’ve bought these cells have found them to be already balanced when they arrive.
2) Just connect them in parallel and leave them for a while (overnight or for a few days) before you build the pack and they’ll balance themselves.
3) The balancer in the BMS will sort out any imbalance, might just take a while.
4) In this application, conservative values are usually used for top and bottom voltages (eg 14.4V to match the alternator voltage instead of 14.6V so the implications of an unbalanced pack are mitigated somewhat).